1. Field of the Invention
The invention relates to closed system urinary drainage bags. More specifically, the invention relates to a device placed in the outlet tube for dispensing an agent for controlling and preventing the retrograde migration of pathogenic microorganisms into the urinary drainage bag.
2. Brief Description of the Prior Art
Urine drainage bags are routinely used by post-operative patients as well as those with urological disorders. Because of injury to the spinal cord, paraplegic patients are unable to control bladder activity and consequently must continuously use a catheter.
In practice, the patient is catheterized and the catheter then connected to the drainage bag through a length of plastic tubing. The bag is normally supported below the level of the patient either from a bed rail or other support and the urine drains by gravity from the patient through the catheter, the tubing and then into a bag via a drip chamber. The bag may be emptied from time to time by means of an outlet tube which is normally closed to prevent leakage. The tube may discharge its contents into any convenient receptacle and then the outlet tube is clamped and the bag reused for the same patient.
The characterized urinary track is one of the most common sites of hospital-acquired infection and in fact accounts for almost thirty percent of such infections. Significant improvements in the prevention of catheter associated infection has been by use of what are known as closed sterile drainage systems. Despite these advances, still over twenty percent of patients with indwelling catheters continue to acquire urinary infections. See Garibaldi et al, New England J. Med., 291: 215-219, 1974. Urine collection bags must be emptied at frequent intervals usually at least once every shift and the removal of bacterially contaminated urine can lead to the spread of urine infection. It is even possible for a patient in the same ward or room shared with a catheterized patient to acquire the infection. In order to minimize cross-contamination, the collected urine must be maintained in sterile condition during the collection period, even when the urine has a high bacterial count when it enters the drainage bag.
Despite the use of the most careful aseptic techniques almost fifty percent of catheterized patients develop an infection when the catheter is in place for twenty-four hours and approximately ninety-eight percent or even more develop an infection of after four days of use of such catheters. This of course is quite harmful to the patient and subjects them to the risk of cystitis and life threatening septicemia. Arch. Internal Med., Vol. 110: 703-711 (1962) and Lancet, Vol. 1,310-312 (1960). The above-noted infections occur due to many circumstances. These include prolonged use of indwelling Foley-type catheters which are often accompanied by absence of sterile insertion and maintenance techniques; having the catheter connected to clean but not sterilized drainage collection containers; and others. The presence of urinary pathogens in the container which multiply and enter the urinary track through the ascending catheter which is a major pathway of infection is quite important. Various attempts have been made to reduce the migration of bacteria through the closed system including the bag, the drip chamber and the tubing connected to the catheter.
The patent to Jinkens et al, U.S. Pat. No. 3,332,442 employs a connector between a catheter and a urine drainage bag for preventing movement of bacteria from the bag to the patient. The three patents of Langston et al, U.S. Pat. Nos. 4,236,517; 4,193,403; and 4,241,733 show a dispensing device which releases paraformaldehyde to control the multiplication of pathogens and prevent migration in catheters. Shaffer U.S. Pat. No. 4,233,263, teaches adding of hydrogen peroxide solution periodically to a urine bag for prevention of bacterial growth. Attempts have been made to provide a one way inlet valve into the urine bag to prevent upward migration. See, for example, U.S. Pat. Nos. 3,312,221 and 4,232,677.
Other attempts have been made to treat the catheter itself with an microbicidal substance. Note U.S. Pat. No. 3,598,127 and the Shepard et al U.S. Pat. Nos. 3,566,874 and 3,695,921 which relate to an antibiotic material in a hydrophilic catheter coating.
U.S. Pat. No. 4,417,892 describes a method of releasing an microbicidal substance by means of a frangible capsule which is inserted into the outlet drainage tube. The capsule must be broken by a nurse or other medical personnel in order to release the active agent.